The Missing Margin: How Sample Corruption Affects Distance to the Boundary in ANNs

Classification margins are commonly used to estimate the generalization ability of machine learning models. We present an empirical study of these margins in artificial neural networks. A global estimate of margin size is usually used in the literature. In this work, we point out seldom considered nuances regarding classification margins. Notably, we demonstrate that some types of training samples are modelled with consistently small margins while affecting generalization in different ways. By showing a link with the minimum distance to a different-target sample and the remoteness of samples from one another, we provide a plausible explanation for this observation. We support our findings with an analysis of fully-connected networks trained on noise-corrupted MNIST data, as well as convolutional networks trained on noise-corrupted CIFAR10 data.Comment: This work is a preprint of a published paper by the same name, which it subsumes. This preprint is an extended version: it contains additional empirical evidence and discussio

The effects on increasing cardiac output with adrenaline or isoprenaline on arterial haemoglobin oxygen saturation and shunt during one-lung ventilation

Publisher's copy made available with the permission of the publisher © 2000 Australian Society of AnaesthetistsTheoretically, if the cardiac output were increased in the presence of a given intrapulmonary shunt, the arterial haemoglobin oxygen saturation (SaO2) should improve as the venous oxygen extraction per ml of blood decreases. To test this hypothesis, eight pigs were subjected to one-lung ventilation and adrenaline and isoprenaline infusions used to increase the cardiac output. The mixed venous oxygen, shunt fraction and oxygen consumption were measured. With both adrenaline and isoprenaline, although there was a small rise in mixed venous oxygen content, there was a fall in SaO2. With adrenaline, the mean shunt rose from 48% to 65%, the mean oxygen consumption rose from 126 ml/min to 134 ml/min and the mean SaO2 fell from 86.9% to 82.5%. With isoprenaline, the mean shunt rose from 45% to 59%, the mean oxygen consumption rose from 121 ml/min to 137 ml/min and the mean SaO2 fell from 89.5% to 84.7%. It is concluded that potential improvement in SaO2, which might occur from a catecholamine-induced increase in mixed venous oxygen content during one-lung ventilation, is more than offset by increased shunting and oxygen consumption which reduce SaO2.W.J. Russell, M.F. Jameshttp://www.aaic.net.au/Article.asp?D=200010

Anaerobic ammonium oxidation in the old trickling filters at Daspoort Wastewater Treatment Works

The century-old trickling filters at the Daspoort Wastewater Treatment Works in Pretoria (Gauteng, South Africa) are known for their remarkable removal of nitrogen from municipal wastewater. Our study was conducted to identify the microbiological processes responsible for this phenomenon and to establish whether anammox bacteria may be involved. An aerobic and anaerobic bench top reactor, both inoculated with biofilm-covered stones from one of the filters, were spiked with ammonia-nitrogen  (NH4+-N) and nitrite-nitrogen (NO2.-N). These reactors were subsequently monitored by conducting stoichiometric analyses of chemical oxygen demand (COD), NH4+-N, NO2.-N, and nitrate-nitrogen (NO3.-N). In the aerobic reactor, the COD concentration decreased over the 56 h batch reaction period and nitrification was revealed by a decrease in NH4+-N and NO2.-N concentrations. However, the NO3.-N concentration showed no  notable decrease. In contrast, in the anaerobic reactor the concentrations of COD, NH4+-N, NO2¡¥-N, NO3¡¥-N, as well as total nitrogen decreased during the batch reaction period. The decrease of both the NH4+-N and NO2.-N concentrations, the latter to zero under anaerobic conditions,   suggested that, in addition to heterotrophic denitrification, anaerobic ammonium oxidation (anammox) may also occur in the trickling filter biofilm. This was highlighted by the observation that ammonium removal in the anaerobic reactor stopped as soon as the nitrite concentration  became zero. The ratio of nitrite:ammonium removal was 1.33 on  average, which conforms to anammox behaviour. Gene sequence analysis was used to test for the possible presence of anammox bacteria in the  trickling filter biofilm. Genomic DNA was extracted from trickling filter  humus sludge and the polymerase chain reaction (PCR) was used to  amplify taxonomically informative 16S rRNA gene sequences, using  primers specific for selected anammox species. Subsequent sequence analysis, including using the online Basic Local Alignment Search Tool (BLAST), and constructing a phylogenic tree using a heuristic search  strategy for Maximum Parsimony analysis, confirmed the presence of an anammox bacterium closely related to Candidatus ¡®Brocadia  anammoxidans¡¯ and Candidatus ¡®Brocadia fulgida¡¯ on the biofilm-covered stones of the Daspoort trickling filters.Keywords: Daspoort, trickling filter, anammox, nitrification, denitrification, stoichiometric analyses, polymerase chain reactio

Nitrofurantoin revisited: a systematic review and meta-analysis of controlled trials

The available evidence supports first-line treatment of lower urinary tract infections with nitrofurantoin as clinical efficacy is similar to that seen for trimethoprim/sulfamethoxazole, ciprofloxacin and amoxicillin, rates of microbiological cure are good, short- term toxicity is generally mild and acquired resistance is still relatively rar

Exposure-Response Relationships for Isavuconazole in Patients with Invasive Aspergillosis and Other Filamentous Fungi

Isavuconazole, the active moiety of the water-soluble prodrug isavuconazonium sulfate, is a triazole antifungal agent for the treatment of invasive fungal infections. The purpose of this analysis was to characterize the isavuconazole exposure-response relationship for measures of efficacy and safety in patients with invasive aspergillosis and infections by other filamentous fungi from the SECURE clinical trial. Two hundred thirty-one patients who received the clinical dosing regimen and had exposure parameters were included in the analysis. The primary drug exposure parameters included were predicted trough steady-state plasma concentrations, predicted trough concentrations after 7 and 14 days of drug administration, and area under the curve estimated at steady state (AUCss). The exposure parameters were analyzed against efficacy endpoints that included all-cause mortality through day 42 in the intent-to-treat (ITT) and modified ITT populations, data review committee (DRC)-adjudicated overall response at end of treatment (EOT)

COVID-19: Are community development scientists missing in action or missing the action?

While the world waits in anticipation for a vaccine against the Covid-19 virus, controlling the spread of the Covid-19 pandemic is all about managing the movement of people. The lockdown principle introduced in many countries aims to keep people in their respective communities, which also means the closure of many formal to the informal local economies. During these times, politicians all over the world rely heavily on the input of scientists when making decisions. Amongst the scientists who seem to play a central role in this process are epidemiologists and economists. But, if this change process is also about communities and communal life, where are the community development experts? Everybody talks about moving to a “new normal” in our societies. If this is to be true, why are the community development specialists so quiet whilst it is all about restoring our communal life